N = int(input())
C = input()

R_cnt = C.count('R')
print(C[:R_cnt].count('W')) N = int(input()) N int(input()) int input() input C = input() C input() input R_cnt = C.count('R') R_cnt C.count('R') C.count C count 'R' print(C[:R_cnt].count('W')) print C[:R_cnt].count('W') [:R_cnt].count [:R_cnt] C :R_cnt R_cnt count 'W' C = input() input() C R_cnt = C.count('R') C.count('R') R_cnt N = int(input()) int(input()) N
N = int(input())
C = input()

R_cnt = C.count('R')
print(C[:R_cnt].count('W'))